# dirivative

1. ### help finding the dirivative

Hi i am trying to find the dirivtive of (4-x^2)^(1/2). I know that i need to use u subsitution and u=4-x^2. Then i get d/dx[u^(1/2)](-2x) then i get stuck, can someone please help me? thank you
2. ### [SOLVED] Dirivative Help [Quotient Rule]

y=\frac{v^3-2v\sqrt{v}}{v} i've tried various techniques and keep getting something like.. =\frac{(3v^2-3v\sqrt{v})-(v^3-2v\sqrt{v})}{v^2} im not sure how to get the answer, but BoB says the answer is y'=\frac{2v-1}{\sqrt{v}} help? maybe you can tell what im doing wrong or what i still...
3. ### struggling to find a dirivative

How do i find the dirivative of y=x-1/2x^2. Thats. y=x - 1 divided by 2x to the power 2. Any help would be greatful. Thanks, James. (where does the math notations everyone seems to use come from? )